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passt/Makefile
Stefano Brivio 06aa26fcf3 Makefile: Hack for optimised-away store in ndp() before checksum calculation
With gcc 11 and 12, passing -flto, or -flto=auto, and -O2,
intra-procedural optimisation gets rid of a fundamental bit in ndp():
the store of hop_limit in the IPv6 header, before the checksum is
calculated, which on x86_64 looks like this:

	ip6hr->hop_limit = IPPROTO_ICMPV6;
    b8c0:	c6 44 24 35 3a       	movb   $0x3a,0x35(%rsp)

Here, hop_limit is temporarily set to the protocol number, to
conveniently get the IPv6 pseudo-header for ICMPv6 checksum
calculation in memory.

With LTO, the assignment just disappears from the binary.

This is rather visible as NDP messages get a wrong checksum, namely
the expected checksum plus 58, and they're ignored by the guest or
in the namespace, meaning we can't get any IPv6 routes, as reported
by Wenli Quan.

The issue affects a significant number of distribution builds,
including the ones for CentOS Stream 9, EPEL 9, Fedora >= 35,
Mageia Cauldron, and openSUSE Tumbleweed.

As a quick workaround, declare csum_unaligned() as "noipa" for gcc
11 and 12, with -flto and -O2. This disables inlining and cloning,
which causes the assignment to be compiled again.

Leave a TODO item: we should figure out if a gcc issue has already
been reported, and report one otherwise. There's no apparent
justification as to why the store could go away.

Reported-by: Wenli Quan <wquan@redhat.com>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2129713
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-29 12:23:11 +02:00

296 lines
10 KiB
Makefile

# SPDX-License-Identifier: AGPL-3.0-or-later
#
# PASST - Plug A Simple Socket Transport
# for qemu/UNIX domain socket mode
#
# PASTA - Pack A Subtle Tap Abstraction
# for network namespace/tap device mode
#
# Copyright (c) 2021 Red Hat GmbH
# Author: Stefano Brivio <sbrivio@redhat.com>
RLIMIT_STACK_VAL := $(shell /bin/sh -c 'ulimit -s')
ifeq ($(RLIMIT_STACK_VAL),unlimited)
RLIMIT_STACK_VAL := 1024
endif
TARGET := $(shell $(CC) -dumpmachine)
# Get 'uname -m'-like architecture description for target
TARGET_ARCH := $(shell echo $(TARGET) | cut -f1 -d- | tr [A-Z] [a-z])
TARGET_ARCH := $(shell echo $(TARGET_ARCH) | sed 's/powerpc/ppc/')
AUDIT_ARCH := $(shell echo $(TARGET_ARCH) | tr [a-z] [A-Z] | sed 's/^ARM.*/ARM/')
AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/I[456]86/I386/')
AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/PPC64/PPC/')
AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/PPCLE/PPC64LE/')
FLAGS := -Wall -Wextra -pedantic -std=c99 -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
FLAGS += -D_FORTIFY_SOURCE=2 -O2 -pie -fPIE
FLAGS += -DPAGE_SIZE=$(shell getconf PAGE_SIZE)
FLAGS += -DNETNS_RUN_DIR=\"/run/netns\"
FLAGS += -DPASST_AUDIT_ARCH=AUDIT_ARCH_$(AUDIT_ARCH)
FLAGS += -DRLIMIT_STACK_VAL=$(RLIMIT_STACK_VAL)
FLAGS += -DARCH=\"$(TARGET_ARCH)\"
PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c icmp.c igmp.c \
isolation.c lineread.c mld.c ndp.c netlink.c packet.c passt.c pasta.c \
pcap.c siphash.c tap.c tcp.c tcp_splice.c udp.c util.c
QRAP_SRCS = qrap.c
SRCS = $(PASST_SRCS) $(QRAP_SRCS)
MANPAGES = passt.1 pasta.1 qrap.1
PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h icmp.h \
isolation.h lineread.h ndp.h netlink.h packet.h passt.h pasta.h \
pcap.h port_fwd.h siphash.h tap.h tcp.h tcp_splice.h udp.h util.h
HEADERS = $(PASST_HEADERS) seccomp.h
# On gcc 11 and 12, with -O2 and -flto, tcp_hash() and siphash_20b(), if
# inlined, seem to be hitting something similar to:
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78993
# from the pointer arithmetic used from the tcp_tap_handler() path to get the
# remote connection address.
#
# TODO: With the same combination, in ndp(), gcc optimises away the store of
# hop_limit in the IPv6 header (temporarily set to the protocol number for
# convenience, to mimic the ICMPv6 checksum pseudo-header) before the call to
# csum_unaligned(). Mark csum_unaligned() as "noipa" as a quick work-around,
# while we figure out if a corresponding gcc issue has already been reported.
ifeq (,$(filter-out 11 12, $(shell $(CC) -dumpversion)))
ifneq (,$(filter -flto%,$(FLAGS) $(CFLAGS)))
ifneq (,$(filter -O2,$(FLAGS) $(CFLAGS)))
FLAGS += -DTCP_HASH_NOINLINE
FLAGS += -DSIPHASH_20B_NOINLINE
FLAGS += -DCSUM_UNALIGNED_NO_IPA
endif
endif
endif
C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_snd_wnd = 0 };
ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
FLAGS += -DHAS_SND_WND
endif
C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_bytes_acked = 0 };
ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
FLAGS += -DHAS_BYTES_ACKED
endif
C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_min_rtt = 0 };
ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
FLAGS += -DHAS_MIN_RTT
endif
C := \#include <sys/random.h>\nint main(){int a=getrandom(0, 0, 0);}
ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
FLAGS += -DHAS_GETRANDOM
endif
ifeq ($(shell :|$(CC) -fstack-protector-strong -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
FLAGS += -fstack-protector-strong
endif
prefix ?= /usr/local
exec_prefix ?= $(prefix)
bindir ?= $(exec_prefix)/bin
datarootdir ?= $(prefix)/share
docdir ?= $(datarootdir)/doc/passt
mandir ?= $(datarootdir)/man
man1dir ?= $(mandir)/man1
ifeq ($(TARGET_ARCH),x86_64)
BIN := passt passt.avx2 pasta pasta.avx2 qrap
else
BIN := passt pasta qrap
endif
all: $(BIN) $(MANPAGES) docs
static: FLAGS += -static -DGLIBC_NO_STATIC_NSS
static: clean all
seccomp.h: seccomp.sh $(PASST_SRCS) $(PASST_HEADERS)
@ EXTRA_SYSCALLS=$(EXTRA_SYSCALLS) ./seccomp.sh $(PASST_SRCS) $(PASST_HEADERS)
passt: $(PASST_SRCS) $(HEADERS)
$(CC) $(FLAGS) $(CFLAGS) $(PASST_SRCS) -o passt $(LDFLAGS)
passt.avx2: FLAGS += -Ofast -mavx2 -ftree-vectorize -funroll-loops
passt.avx2: $(PASST_SRCS) $(HEADERS)
$(CC) $(filter-out -O2,$(FLAGS) $(CFLAGS)) \
$(PASST_SRCS) -o passt.avx2 $(LDFLAGS)
passt.avx2: passt
pasta.avx2 pasta.1 pasta: pasta%: passt%
ln -s $< $@
qrap: $(QRAP_SRCS) passt.h
$(CC) $(FLAGS) $(CFLAGS) $(QRAP_SRCS) -o qrap $(LDFLAGS)
valgrind: EXTRA_SYSCALLS="rt_sigprocmask rt_sigtimedwait rt_sigaction \
getpid gettid kill clock_gettime mmap munmap open \
unlink gettimeofday futex"
valgrind: FLAGS:=-g -O0 $(filter-out -O%,$(FLAGS))
valgrind: all
.PHONY: clean
clean:
$(RM) $(BIN) *.o seccomp.h pasta.1 \
passt.tar passt.tar.gz *.deb *.rpm \
passt.pid README.plain.md
install: $(BIN) $(MANPAGES) docs
mkdir -p $(DESTDIR)$(bindir) $(DESTDIR)$(man1dir)
cp -d $(BIN) $(DESTDIR)$(bindir)
cp -d $(MANPAGES) $(DESTDIR)$(man1dir)
mkdir -p $(DESTDIR)$(docdir)
cp -d README.plain.md $(DESTDIR)$(docdir)/README.md
cp -d doc/demo.sh $(DESTDIR)$(docdir)
uninstall:
$(RM) $(BIN:%=$(DESTDIR)$(prefix)/bin/%)
$(RM) $(MANPAGES:%=$(DESTDIR)$(man1dir)/%)
$(RM) $(DESTDIR)$(docdir)/README.md
$(RM) $(DESTDIR)$(docdir)/demo.sh
-rmdir $(DESTDIR)$(docdir)
pkgs: static
tar cf passt.tar -P --xform 's//\/usr\/bin\//' $(BIN)
tar rf passt.tar -P --xform 's//\/usr\/share\/man\/man1\//' \
$(MANPAGES)
gzip passt.tar
EMAIL="sbrivio@redhat.com" fakeroot alien --to-deb \
--description="User-mode networking for VMs and namespaces" \
-k --version=$(shell git rev-parse --short HEAD) \
passt.tar.gz
fakeroot alien --to-rpm --target=$(shell uname -m) \
--description="User-mode networking for VMs and namespaces" \
-k --version=g$(shell git rev-parse --short HEAD) passt.tar.gz
# TODO: This hack makes a "plain" Markdown version of README.md that can be
# reasonably shipped as documentation file, while the current README.md is
# definitely intended for web browser consumption. It should probably work the
# other way around: the web version should be obtained by adding HTML and
# JavaScript portions to a plain Markdown, instead. However, cgit needs to use
# a file in the git tree. Find a better way around this.
docs: README.md
@( \
skip=0; \
while read l; do \
case $$l in \
"## Demo") exit 0 ;; \
"<!"*) ;; \
"</"*) skip=1 ;; \
"<"*) skip=2 ;; \
esac; \
\
[ $$skip -eq 0 ] && echo "$$l"; \
[ $$skip -eq 1 ] && skip=0; \
done < README.md; \
) > README.plain.md
# Checkers currently disabled for clang-tidy:
# - llvmlibc-restrict-system-libc-headers
# TODO: this is Linux-only for the moment, nice to fix eventually
#
# - bugprone-macro-parentheses
# - google-readability-braces-around-statements
# - hicpp-braces-around-statements
# - readability-braces-around-statements
# Debatable whether that improves readability, right now it would look
# like a mess
#
# - readability-magic-numbers
# - cppcoreguidelines-avoid-magic-numbers
# TODO: in most cases they are justified, but probably not everywhere
#
# - clang-analyzer-valist.Uninitialized
# TODO: enable once https://bugs.llvm.org/show_bug.cgi?id=41311 is fixed
#
# - clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling
# Probably not doable to impement this without plain memcpy(), memset()
#
# - cppcoreguidelines-init-variables
# Dubious value, would kill readability
#
# - hicpp-signed-bitwise
# Those are needed for syscalls, epoll_wait flags, etc.
#
# - llvm-include-order
# TODO: not really important, but nice to fix eventually
#
# - readability-isolate-declaration
# Dubious value, would kill readability
#
# - bugprone-narrowing-conversions
# - cppcoreguidelines-narrowing-conversions
# TODO: nice to fix eventually
#
# - cppcoreguidelines-avoid-non-const-global-variables
# TODO: check, fix, and more in general constify wherever possible
#
# - altera-unroll-loops
# - altera-id-dependent-backward-branch
# TODO: check paths where it might make sense to improve performance
#
# - bugprone-easily-swappable-parameters
# Not much can be done about them other than being careful
#
# - readability-function-cognitive-complexity
# TODO: split reported functions
#
# - altera-struct-pack-align
# "Poor" alignment needed for structs reflecting message formats/headers
#
# - concurrency-mt-unsafe
# TODO: check again if multithreading is implemented
#
# - readability-identifier-length
# Complains about any identifier <3 characters, reasonable for
# globals, pointlessly verbose for locals and parameters.
clang-tidy: $(SRCS) $(HEADERS)
clang-tidy -checks=*,-modernize-*,\
-clang-analyzer-valist.Uninitialized,\
-cppcoreguidelines-init-variables,\
-bugprone-macro-parentheses,\
-google-readability-braces-around-statements,\
-hicpp-braces-around-statements,\
-readability-braces-around-statements,\
-readability-magic-numbers,\
-llvmlibc-restrict-system-libc-headers,\
-hicpp-signed-bitwise,\
-clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling,\
-llvm-include-order,\
-cppcoreguidelines-avoid-magic-numbers,\
-readability-isolate-declaration,\
-bugprone-narrowing-conversions,\
-cppcoreguidelines-narrowing-conversions,\
-cppcoreguidelines-avoid-non-const-global-variables,\
-altera-unroll-loops,-altera-id-dependent-backward-branch,\
-bugprone-easily-swappable-parameters,\
-readability-function-cognitive-complexity,\
-altera-struct-pack-align,\
-concurrency-mt-unsafe,\
-readability-identifier-length \
-config='{CheckOptions: [{key: bugprone-suspicious-string-compare.WarnOnImplicitComparison, value: "false"}]}' \
--warnings-as-errors=* $(SRCS) -- $(filter-out -pie,$(FLAGS) $(CFLAGS))
SYSTEM_INCLUDES := /usr/include $(wildcard /usr/include/$(TARGET))
ifeq ($(shell $(CC) -v 2>&1 | grep -c "gcc version"),1)
VER := $(shell $(CC) -dumpversion)
SYSTEM_INCLUDES += /usr/lib/gcc/$(TARGET)/$(VER)/include
endif
cppcheck: $(SRCS) $(HEADERS)
cppcheck --std=c99 --error-exitcode=1 --enable=all --force \
--inconclusive --library=posix --quiet \
$(SYSTEM_INCLUDES:%=-I%) \
$(SYSTEM_INCLUDES:%=--config-exclude=%) \
$(SYSTEM_INCLUDES:%=--suppress=*:%/*) \
$(SYSTEM_INCLUDES:%=--suppress=unmatchedSuppression:%/*) \
--inline-suppr \
--suppress=unusedStructMember \
$(filter -D%,$(FLAGS) $(CFLAGS)) \
.